Shielded memory card holder

Abstract: This invention is directed to a fully shielded printed circuit (PC) card holder, that may be readily "snapped" into the assembly, or disassembled, as the case may be. The holder is intended to receive a PC card, where at least one end of the card is adapted to be electrically connected to an I/O type connector. The holder comprises a generally rectangular bottom cover member formed of a conductive material, corner supports integrally molded to said bottom cover member at the respective corners thereof, where each said support includes a lower flange portion to which said bottom cover member is exposed. Further, a generally rectangular upper cover member is provided where the periphery thereof includes a downwardly extending flange adapted to engage the lower flange portion in electrical contact with the bottom cover member over a substantial portion of the periphery thereof. In the assembled condition, the holder provides continuous shielding against distortion of data signals between the PC card and the I/O type connector.

Description: This invention relates to memory cards and more particularly to a shielding apparatus for memory cards. With the advent of sophisticated computers, facsimile machines, printers, and other computer-related electronics equipment, the need for external printed circuit (PC) interface to be used by the computer and computer-related equipment is ever increasing. To this end, memory cards containing external memory and data to be used in computer processes have been designed. At the present time, there are three different memory card types, as defined by the Personal Computer Memory Card International Association (PCMCIA). This is the standards body responsible for developing the 68-pin memory card standard. The three memory card types, are as follows: a. Type I Memory Cards are the same width and length as a common credit card, 54mm x 85.6mm, but are thicker than a credit card. The thickness of a Type I card is 3.3mm (.130"). b. Type II Memory Cards are used by those companies which are utilizing memory components that are too high to be housed within a Type I card. Type II memory cards are also the same overall length and width as credit cards, but have raised body cross section in the substrate area which gives them an overall thickness of 5mm (.195"). The raised substrate areas of these cards are 48mm in width. c. Type III Memory Cards are the result of a recent movement sponsored by the Small Form Factor Committee (SFF) to enable 1.8" Small Form Factor Disk Drives to be plugged into memory card connectors in small portable computer applications. Type III Memory Cards are the same length and width as Type I and Type II Cards. However, Type III Cards have a substrate area thickness of 10.5mm. Also, Type III Cards require a card guide opening width of 51mm of the header connector to accommodate the slightly raised substrate area. Memory cards generally comprise a printed circuit board, a casing made of an insulating material for housing the printed circuit board, and at least one connector, typically referred to as an "I/O" connector. The connector is provided on one end of the casing for interfacing the memory card, and particularly the printed circuit board contained in the casing, to the computer equipment to which the card is mated. The connector is designed to extract the contents of the memory stored on the printed circuit board and to bus data to and from an outside environment, which also usually comprises a computer or other electronic equipment. In this fashion, data traverses the interface between the card and the outside environment so that the data can be efficiently transferred and used by the computer to which the card is mated for its intended purpose. Memory cards are generally interchangeable and can be used with many different machines and electronic components. Because the cards are interchangeable, they undergo a significant amount of abuse when transported, interfaced and mated to the different computers and electronic equipment which use them. Since a card is conventionally made up of a number of layers and/or elements glued or otherwise bonded together, the individual layers tend to become loose and/or separated from one another as the memory card is subject to flexing stress, as typically occurs when the card is inserted into or removed from the electronic or other computer-type equipment. Thus, even after moderate amounts of usage, conventional memory cards have heretofore frequently become structurally loose, and the internal members of the card often become misaligned. This results in failure of the memory card and degrades the performance of the electronic equipment which uses the card. These undesirable results generally induce poor performance of the computer system which uses the memory card. Another undesirable result which induces poor performance of the computer system results from inadequate shielding of the card and the connectors electrically connected thereto. In the prior art, memory cards had separate shields which were provided proximate the various components of the card. This discontinuous shielding provided breaks in the shielding and limited the effectiveness of the memory card, particularly in environments in which many electronic devices were located. Notwithstanding the above, US-A-Patent No. 5,005,106 teaches a system for providing continuous shielding to a substrate. Specifically, the patent teaches the use of a flexible, conductive envelope into which the substrate may be inserted, then placed within an insulative housing. From document EP-A-0 040 753 an insulated high-voltage mounting rack to be inserted into an opening of a housing has come to be known. In particular, this known device comprises a shielded card holder for receiving an electrical circuit card therein, comprising upper and lower shield members covering said card, said shell members having interengaging sections maintaining said shield members together and covering said card whereby the shield members can be disengaged from another. From EP-A-0 459 044 there is further known an IC card having a card body with a frame and a plurality of slits extending through the frame in the thicknesswise direction, and a pair of metallic panels secured to the card body. The metallic panels have engaging portions which extend into the slits when the metallic panels are secured to the card body so that the engaging portions of both panels engage with each other within each slit e.g. by claws and retainers, so as to fasten both metallic panels to the card body. The electrical potentials of both metallic panels are equalized through these engaging portions. The present invention avoids these undesirable results or complexities by the provision of a continuous shielding arrangement that is easy to assemble. The uniqueness of this arrangement will become apparent from the description which follows, particularly when read in conjunction with the accompanying drawings. This invention as defined in claim 1 is directed to a shielded memory card holder, particularly for Type I and Type II Cards, where such holder offers continuous shielding thereto, by the combination of a bottom cover integrally molded to the card frame and a cover member that will snap fit onto said bottom cover/frame. The holder comprises a generally rectangular bottom cover formed of a conductive material, and corner supports integrally molded to the bottom cover at the respective corners thereof, where each support includes a lower flange portion to which the bottom cover is exposed. Matable therewith is a generally rectangular upper cover whose periphery includes a downwardly extending flange adapted to engage the lower flange portion in electrical contact with the bottom cover over a substantial portion of the periphery thereof, thereby to providing continuous shielding against distortion of data signals between the PC card and an I/O type connector. The invention provides a shielded memory card holder for receiving a memory card therein comprising upper and lower shield members covering the memory card, the shield members have interengaging sections maintaining the shield members together covering the memory card whereby the shield members can be disengaged from each other. An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: FIGURE 1 is a perspective view of an assembled, fully shielded memory card holder according to this invention. FIGURE 2 is an exploded, perspective view, including a PC card for containment therein, of the memory card holder of Figure 1. FIGURE 3 is a sectional view taken along line 3-3 of Figure 2. FIGURE 4 is an enlarged, partial, sectional view of the PC card holder of Figure 2, taken of a longitudinal section. FIGURE 5 is an enlarged, partial, sectional view of the memory card holder of Figure 4, in an assembled and shielded position. FIGURE 6 is an enlarged, partial, sectional view taken through the integral grounding clip, forming part of the upper cover member. FIGURE 7 is an enlarged, partial, sectional view of the memory card holder of Figure 6, in an assembled and shielded position, taken along line 7-7 of Figure 1. FIGURE 8 is an enlarged, partial, sectional view taken along line 8-8 of Figure 1. FIGURE 9 is a view similar to Figure 8 illustrating the manner by which the card holder of this invention may be disassembled. Referring now to the several Figures representing the preferred embodiment of this invention, Figures 1 and 2 illustrate an assembled and exploded views respectively, of the memory card holder 10 comprising a bottom cover member 12 of a conductive material, such as metal, integrally molded with a dielectric frame 14, and an upper cover member 16, stamped and formed of a conductive material, such as metal, where such cover members 12, 16 are adapted to receive and provide shielding to a card 20 therebetween. A typical memory card may consist of a printed circuit board (PCB), as known in the art, or other type of planar circuit element adapted to store, receive and/or transmit data. Additionally, the card 20 may be provided with at least one connector as known in the art disposed in a receiving cavity 22 therefor so that the connector may mechanically and electrically interface with the card 20. The card 20 preferably requires a second connector, not shown, such as along the opposite edge 28, for mating the card to a computer or other device (not shown) which will utilize the card's memory and/or perform computer operations on data which is stored in the card and/or received from the outside environment through the connector in cavity 22. In general, the computer or second connector is of a two-piece construction having a posted header for connection onto the host equipment, such as a computer, and a receptacle assembly which is used by the card 10, as known in the art. Returning now to the holder 10, specifically the integrally molded bottom cover 12 and frame 14, the frame thereof includes a pair of side rails 30 having exposed longitudinally surface portions 32 for receiving and supporting the contained card 20. Additionally, the frame 14 may include at least one transverse member 34 to provide structural integrity to the frame and support for the memory card. As best seen in the sectional views of Figures 3-5, the bottom cover member 12 is essentially a planar member disposed outside the frame 14, except at the edges 36 thereof. The bottom cover member 12 is formed at its edge 36 to yield a peripheral shoulder portion 38 and an upturned edge 40 which is integrally molded into the frame 14, thereby fixing the relative position of the bottom cover member 12 to the frame 14. Along the side rails 30, plural spaced-apart recesses 42 have been provided. As will be explained hereinafter, in connection with Figures 8 and 9, such recesses 42 facilitate the receipt of a suitable tool to allow for the easy removal of the cover member 16 for replacement of the card 20. Additionally, a further single recess 44 is included along one of said side rails 30 to accommodate an inturned grounding tab 46, the design and function of which is best illustrated in Figures 6 and 7. Returning now to the upper cover member 16, which is intended to be 'snap' fitted onto the Frame 14 in electrical contact with bottom cover 12, the major or longitudinal sides 50 are characterized by essentially continuous inturned flanges 52. The transverse edges 54 are discontinuous to the extent that each may accommodate a connector for engagement with the PC card 20, typically along a midpoint thereof. However, at least at the ends 56 thereof, such ends 56 further include inwardly directed flanges 58 for engagement with the frame 14. To facilitate the assembly of the PC card holder 10, after placing a memory card 20 therein along surface portions 32, it will be noted that side rails 30 have tapered surfaces 60, see Figures 4-7, such that as the upper cover flanges 52 contact the tapered surfaces 60 and the flanges flex outward until they reach the lower most edge 62, then resile into contact with the exposed shoulder portion 38 (figure 8). Figure 5 best illustrates the latching arrangement of the holder assembly, where it will be seen that the flanges 52 of the upper cover are spaced from the tapered or camming surfaces 60 and remain in a slightly flexed position so as to insure a constant gripping force and electrical engagement between the respective cover members. As noted previously, the upper cover member 16, stamped and formed from a sheet metal blank, is provided with a grounding tab or strap 46 aligned with the recess 44. The end 70 of the tab 46 includes a flat portion which is adapted to engage grounding traces, as known in the art on the surface 72 of PC card 20 (Figure 7), thereby assuring suitable grounding thereof. Figures 8 and 9 demonstrate the manner by which the cover members 12, 16 may be readily separated, as desired. The side rails 30 of the frame 14 have been provided with the plural recesses 42. When disassembly of the holder 10 is required, a suitable bladed tool, where the blade 80 is shown in Figures 8 and 9, may be inserted at the contact edge 62, between the cover members 12, 16 into the recesses 42. With this action, the flanges 52 are flexed outwardly and freed of the outermost edge 62 for easy removal. A preferred tool for such assembly, though not illustrated in the several figures, can be a planar member, coextensive in dimension to the bottom cover member 16, having plural blade-like lances projecting therefrom so that such action is uniformly applied about the periphery of the holder. Thus, by this construction, the holder 10 may be readily assembled, or disassembled, while providing effective shielding during the use thereof. ADVANTAGES OF THE INVENTION An advantage of the present invention is a shielded memory card holder whereby shield members are held together covering a memory card positioned therebetween such that they are easy to assemble and disassemble. Another advantage of the invention is a dielectric frame secured to one of the shield members which provides surface portions for supporting a memory card and which provides structural integrity.

Claims: A shielded card holder for receiving an electrical circuit card (20) therein, a) comprising upper and lower shield members (12, 16) covering said card (20), b) said shield members (12, 16) having interengaging sections (14, 38, 50, 52) maintaining said shield members (12, 16) together covering said card (20) whereby the shield members (12, 16) can be disengaged from one another, characterized in that c) said electrical circuit card (20) is a memory card, d) the interengaging sections (14, 38, 50, 52) consist of a frame (14) integrally molded about the periphery to one of said shield members (12), e) the other of said shield members (16) having flanges (52) adapted to engage said frame (14) to effect an electrical connection between said shield members (12, 16) and maintain said shield members (12, 16) together to shield and cover said memory card. A shielded card holder as claimed in claim 1, characterized in that a) said frame (14) has side rails (30) integrally molded to said shield members (12) and b) wherein tapered surfaces (60) are provided along said flanges (52) of shield member (16) for snap engagement therewith. A shielded card holder as claimed in claim 2, characterized in that said rails (30) have recess (42) for receiving a disassembly tool to disengage the shield members. A shield card holder as claimed in any of claims 1 to 3, characterized in that one of said shield members (12, 16) includes a grounding tab (46) for electrically engaging a ground trace on the memory card. A shielded card holder as claimed in any of claims 2 to 4, characterized in that said frame (14) comprises surface portions (32) for supporting the memory card thereon. A shielded card holder as claimed in any of claims 1 to 5, characterized in that an electrical connector (22) is connected to the memory card and disposed between the shield members (12, 16).

Inventors: BARKER RILEY KEITH, SIMMONS RANDY GRAY, SIZEMORE RONALD DILLON, BARKER, RILEY KEITH, SIMMONS, RANDY GRAY, SIZEMORE, RONALD DILLON
Applicants: WHITAKER CORP, THE WHITAKER CORPORATION
Application year: 1994
Main classification: H05K9
IPC codes: G06F1, H05K7, H05K5, G06K19, G06F12, H05K9